Vandersteen Audio 2Ce loudspeaker Sidebar 3: Measurements
The Vandersteen 2Ce's impedance curve in fig.1 indicates a load which should be easy to drive. The magnitude of the impedance never drops below 4 ohms. Though the 2Ce is said to function as a sealed box, the low-frequency impedance is reminiscent of the double peak response typical of reflex enclosures. But the upper peak is heavily damped. The box tuning appears to be about 41.3Hz—the minimum between the two peaks. The magnitude of the impedance at mid and high frequencies differs only slightly with the setting of the contour controls (the upper curve shows both controls set at minimum, the center at the 12 o'clock position, and the lower with both controls set at maximum). The sensitivity of the 2Ce, with 2.83V in, was low at around 82dB at 1 meter.
The impulse response of the Vandersteen, taken on the tweeter axis, is shown in fig.2. The pulse has good symmetry, largely due to the first-order filters employed. The slow rise in the first fraction of a millisecond is from the midrange driver; the tweeter's contribution comes in almost immediately thereafter, increasing the steepness of the response; the midrange and tweeter have excellent time coherence. The small ripple in the response visible between about 6ms and 7ms is a room reflection. The latter is exaggerated in the step response (fig.3) because of the effective LF boost. The shape of this step response also shows the good time coherency, but with a sharp initial spike indicative of at least some high-frequency emphasis.